Paul Pecknold, Professor, Botany & Plant Pathology, Purdue University

Once again fireblight was the most prominent disease, causing significant damage throughout the state, but especially in areas of southern Indiana. First reports of fireblight were received from growers in the southern areas of the state and from there it proceeded northward. We suspect a major contributing factor to this year’s fireblight was the continued build up of holdover cankers from the previous four years. Blister spot of Crispin, another bacterial disease, was also more evident this year. We suspect that extensive rainy periods in late spring contributed to the increased occurrence of blister spot. The season started off on the wet side, resulting in numerous early season primary scab infection periods along with an increase in cedar apple and cedar quince rust. However an early wet season gave way to a dry summer resulting in a diminished buildup of secondary scab or other summer diseases. The early wet weather did cause an increase in reports of phytopthora crown rot on both apples and stone fruit.